[PATCH v5 03/13] iommufd: Add iommufd_verify_unfinalized_object
Nicolin Chen
nicolinc at nvidia.com
Tue Oct 29 21:05:14 PDT 2024
On Tue, Oct 29, 2024 at 03:55:58PM -0300, Jason Gunthorpe wrote:
> On Tue, Oct 29, 2024 at 09:18:05AM -0700, Nicolin Chen wrote:
> > I think we'd need the same change in iommufd_object_abort() too.
>
> Makes sense
I found xa_cmpxchg() does xas_result to its returning value, which
turns XA_ZERO_ENTRY into NULL failing our intended verifications.
So, I replaced that further with xas_store:
-----------------------------------------------------------------
@@ -41,20 +41,26 @@ static struct miscdevice vfio_misc_dev;
void iommufd_object_finalize(struct iommufd_ctx *ictx,
struct iommufd_object *obj)
{
+ XA_STATE(xas, &ictx->objects, obj->id);
void *old;
- old = xa_store(&ictx->objects, obj->id, obj, GFP_KERNEL);
- /* obj->id was returned from xa_alloc() so the xa_store() cannot fail */
- WARN_ON(old);
+ xa_lock(&ictx->objects);
+ old = xas_store(&xas, obj);
+ xa_unlock(&ictx->objects);
+ /* obj->id was returned from xa_alloc() so the xas_store() cannot fail */
+ WARN_ON(old != XA_ZERO_ENTRY);
}
/* Undo _iommufd_object_alloc() if iommufd_object_finalize() was not called */
void iommufd_object_abort(struct iommufd_ctx *ictx, struct iommufd_object *obj)
{
+ XA_STATE(xas, &ictx->objects, obj->id);
void *old;
- old = xa_erase(&ictx->objects, obj->id);
- WARN_ON(old);
+ xa_lock(&ictx->objects);
+ old = xas_store(&xas, NULL);
+ xa_unlock(&ictx->objects);
+ WARN_ON(old != XA_ZERO_ENTRY);
kfree(obj);
}
-----------------------------------------------------------------
Thanks
Nicolin
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